This SCOR program is the coalescence of six distinct research activities that yield information about the SCOR theme, which is The Formation, Size and Distribution Kinetics of Calcium Salt Particles in the Urinary Tract. The six research activities cover human and animal nutrition, crystalluria analysis, stone and stone matrix ultrastructure of crystal-cell interfaces, and physical chemistry of urine-electrolyte solutions and precipitation systems. These diverse areas of research provide an integrated program that concerns itself with basic mechanisms in urolithiasis.